Image noise reduction is an important link in image processing. For example, during the processing of a medical image, due to the problems such as inadequate signal detection performance and imaging algorithm of an apparatus, low dosage of scanning agent and the like, noise is generally contained in a medical image obtained by a computed tomography (CT) apparatus, a magnetic resonance imaging (MRI) apparatus, an ultrasound (UL) diagnostic apparatus and other medical apparatuses. The noise in such images will cause a severe influence on the diagnosis of a doctor as well as an influence on the accuracy of the subsequent image processing (e.g. image segmentation, image measurement and volume rending).